Busch Rapid Aplanat

[Richard Kelham]

I've recently been given a box of old LF lenses, most of them in pretty rough condition, but the best is also probably the oldest: an Emil Busch Rapid Aplanat no.5 which is an 18 inch f8 lens in a lovely brass mount.

What I have not been able to on the net (and in the archives here) is any info about the angle of view/coverage of this lens. It would be useful to know so I can make up a lens board to suit – though it's going to stretch the bellows to the limit on both 5x4 and 10x8 cameras!


Richard

[Dan Fromm]

The VM says "Rapid Aplanat f8.0 This was made in 6, 8, 10, 13, 18, 24in.and has been noted as 150, 200, 300mm
and will be on plate cameras rather than later types. It covers 70-75° and it was suggested to use 10in for
1/1plate, while 8in covers 10x8in at small stops. (Bus 008) A German advert. lists 15cm for 65x100mm at f8,
9x12 at f12 and 13x18 fully stopped down. Then it was made as Series F in 150, 200 and 260cm."

[brook]

As I recall, an aplant is basically a rapid rectilliner design, and the coverage should far exceed the needs of either format, althought I dont know the degree of coverage. I have a 15" Voigtlander RR that easily covers 11x14 with movement.

[Richard Kelham]

Thanks Dan.

So, with an angle of 70º an 18inch lens will cover....half my kitchen wall!

In the new year I'll make a lens board for the Kodak 2D and see what it's like. Unfortunately my 2D doesn't have the extension rail so it will be a bit of a squeeze.


Richard

[Ole Tjugen]

The VM says "Rapid Aplanat f8.0 This was made in 6, 8, 10, 13, 18, 24in.and has been noted as 150, 200, 300mm
and will be on plate cameras rather than later types...

For a change, the VM is correct - as far as it goes.

The Busch Serie D Rapidaplanat F/8 was made in 150, 200, 260, 340, 470 and 600mm versions.

In general the coverage of "Universal Aplanats" is 30 degrees at full aperture, increasing to 60 degrees at small stops. That's what my book calls "general sharpness", and then goes on to say that "portrait coverage" is much greater. This is true for ALL f:7 to f:8 Aplanats. There are faster "Portraitaplanats" with less coverage, and slower (around f:12 to f:15) "Weitwinkelaplanats" with much greater coverage - in some cases up to 110 degrees.

So your 470mm lens should cover 30x40cm with room to spare - about the same as my Suter 480mm...